Sealing points between the housing and the rotor are designed as labyrinth seals in axial rotary machines and turbocompressors used for hot gas operation.
To increase the sealing action, so-called honeycomb seals are used as opposing running surfaces of the sealing tips of the rotor blade in the first turbine stage after the entry of the compressed hot gases from the bifurcated pipe.
For hot gas operation of the turbine, these honeycomb seals are made of high temperature-resistant Ni-base alloys. In the case of a further increase in the operating temperature, the temperature of the material of the honeycomb seal was reduced hitherto by a housing wall cooling or external film cooling to a limited extent only in a gas turbine developed by the applicant.
Due to the generally insufficient cooling of the seal, sealing tips, rotor blade and other components in the first turbine stage of the gas turbine, excessively high material temperatures were observed on the welded parts, which adversely affected the oxidation and corrosion resistance and led to unacceptable sealing losses.